3-D Printed Protective Equipment during COVID-19 Pandemic

While the number of coronavirus cases from 2019 continues to grow, hospitals are reporting shortages of personal protective equipment (PPE) for frontline healthcare workers. Furthermore, PPE for the eyes and mouth, such as face shields, allow for additional protection when working with aerosols. 3-D printing enables the easy and rapid production of lightweight plastic frameworks based on open-source data. The practicality and clinical suitability of four face shields printed using a fused deposition modeling printer were examined. The weight, printing time, and required tools for assembly were evaluated. To assess the clinical suitability, each face shield was worn for one hour by 10 clinicians and rated using a visual analogue scale. The filament weight (21-42 g) and printing time (1:40-3:17 h) differed significantly between the four frames. Likewise, the fit, wearing comfort, space for additional PPE, and protection varied between the designs. For clinical suitability, a chosen design should allow sufficient space for goggles and N95 respirators as well as maximum coverage of the facial area. Consequently, two datasets are recommended. For the final selection of the ideal dataset to be used for printing, scalability and economic efficiency need to be carefully balanced with an acceptable degree of protection

Fully guided implant surgery using Magnetic Resonance Imaging – An in vitro study on accuracy in human mandibles

Objectives: The objective of this in vitro study was to assess the accuracy of fully guided implant placement following virtual implant planning based on MRI. Material and methods: Sixteen human cadaver hemimandibles with single missing teeth (n = 3), partially edentulous (n = 6) and edentulous situations (n = 7) were imaged using MRI. MRI and optical scans obtained with an intraoral scanner, were imported into an implant planning software. Virtual prosthetic and implant planning were performed regarding hard- and soft-tissue anatomy. Drill guides were manufactured, and fully guided implant placement was performed. Buccal and lingual bone and implant nerve distance were measured by three examiners in preoperative MRI and postoperative CBCT. The implant position was assessed using a software for deviation of implant positions displayed in CBCT and optical scans, respectively. Results: MRI displayed relevant structures for implant planning such as cortical and cancellous bone, inferior alveolar nerve and neighboring teeth. Implant planning, CAD/CAM of drill guides and guided implant placement were performed. Deviations between planned and actual implant positions in postoperative CBCT and optical scans were 1.34 mm (SD 0.84 mm) and 1.03 mm (SD 0.46 mm) at implant shoulder; 1.41 mm (SD 0.88 mm) and 1.28 mm (SD 0.52 mm) at implant apex, and 4.84° (SD 3.18°) and 4.21° (SD 2.01°). Measurements in preoperative MRI and postoperative CBCT confirmed the compliance with minimum distances of implants to anatomical structures. Conclusions: Relevant anatomical structures for imaging diagnostics in implant dentistry are displayed with MRI. The accuracy of MRI-based fully guided implant placement in vitro is comparable to the workflow using CBCT

Impurities in commercial titanium dental implants – A mass and optical emission spectrometry elemental analysis

Objective: Titanium (Ti) is considered bioinert and is still regarded as the “gold standard” material for dental implants. However, even ‘commercial pure’ Ti will contain minor fractions of elemental impurities. Evidence demonstrating the release of Ti ions and particles from ‘passive’ implant surfaces is increasing and has been attributed to biocorrosion processes which may provoke immunological reactions. However, Ti observed in peri-implant tissues has been shown to be co-located with elements considered impurities in biomedical alloys. Accordingly, this study aimed to quantify the composition of impurities in commercial Ti dental implants. Methods: Fifteen commercial titanium dental implant systems were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS) and optical emission spectrometry (ICP-OES). Results: The elemental composition of implants manufactured from commercially pure grades of Ti, Ti-6Al-4V, and the TiZr alloy (Roxolid) conformed to the respective ISO/ASTM standards or manufacturers´ data (TiZr/Roxolid). However, all implants investigated included exogenous metal contaminants including Ni, Cr, Sb, and Nb to a variable extent. Other contaminants detected in a fraction of implants included As and the radionuclides U-238 and Th-232. Significance: Although all Ti implant studies conformed with their standard compositions, potentially allergenic, noxious metals and even radionuclides were detected. Since there are differences in the degree of contamination between the implant systems, a certain impurity fraction seems technically avoidable. The clinical relevance of these findings must be further investigated, and an adaptation of industry standards should be discussed

Three water restriction schedules used in rodent behavioral tasks transiently impair growth and differentially evoke a stress hormone response without causing dehydration

Water restriction is commonly used to motivate rodents to perform behavioral tasks; however, its effects on hydration and stress hormone levels are unknown. Here, we report daily body weight and bi-weekly packed red blood cell volume and corticosterone in adult male rats across 80 days for three commonly used water restriction schedules. We also assessed renal adaptation to water restriction using post-mortem histological evaluation of renal medulla. A control group received ad libitum water. After one week of water restriction, rats on all restriction schedules resumed similar levels of growth relative to the control group. Normal hydration was observed, and water restriction did not drive renal adaptation. An intermittent restriction schedule was associated with an increase in corticosterone relative to the control group. However, intermittent restriction evokes a stress response which could affect behavioral and neurobiological results. Our results also suggest that stable motivation in behavioral tasks may only be achieved after one week of restriction.Peer reviewe

Characterization of macrophages infiltrating periâ implantitis lesions

ObjectivesThe mechanisms involved in the initiation and progression of periâ implantitis lesions are poorly understood. It was the aim to determine the content and activation status of macrophages present in human periâ implantitis lesions and compare the current findings with the macrophage polarization associated with periodontitis lesions.Material and MethodsA total of 14 patients were studied in this investigation. Seven were soft tissue biopsies from dental implants affected by periâ implantitis that required explantation. Seven biopsies were from chronic periodontal disease. Immunofluorescence stains were performed using biomarkers to identify macrophages (CD68+) undergoing M1 polarization (iNOS+) and M2 polarization (CD206+), along with Hoechst 33,342 to identify DNA content. All samples were stained and photographed, and doubleâ positive cells for CD68 and iNOS or CD68 and CD206 were quantified.ResultsAll periâ implantitis biopsies examined revealed a mixed population of macrophages undergoing M1 polarization and M2 polarization. Further analysis demonstrated the coâ expression of iNOS and CD206, which indicates the presence of a heterogenic immune response on periâ implantitis lesions. Macrophage polarization in periâ implantitis lesions presents a distinct pattern than in periodontitis. We observed a significant increase in the population of M1 macrophages on periâ implantitis samples compared to periodontal disease samples.ConclusionOur results demonstrate that periâ implantitis has higher numbers of macrophages displaying a distinct macrophage M1 polarization signature compared to periodontitis lesions. This pattern may explain, in part, the distinct nature of periâ implantitis progression vs. periodontitis in humans.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154542/1/clr13568_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154542/2/clr13568.pd

A matter of origin - identification of SEMA3A, BGLAP, SPP1 and PHEX as distinctive molecular features between bone site-specific human osteoblasts on transcription level

In oral and maxillofacial bone reconstruction, autografts from the iliac crest represent the gold standard due to their superior clinical performance, compared to autografts derived from other extraoral regions. Thus, the aim of our study was to identify putative differences between osteoblasts derived from alveolar (hOB-A) and iliac crest (hOB-IC) bone of the same donor (nine donors) by means of their molecular properties in 2D and 3D culture. We thereby focused on the gene expression of biomarkers involved in osteogenic differentiation, matrix formation and osteoclast modulation. Furthermore, we examined the transcriptional response to Vit.D3 in hOB-A and hOB-IC. Our results revealed different modulation modes of the biomarker expression in osteoblasts, namely cell origin/bone entity-dependent, and culture configuration- and/or time-dependent modulations. SEMA3A, SPP1, BGLAP and PHEX demonstrated the strongest dependence on cell origin. With respect to Vit.D3-effects, BGLAP, SPP1 and ALPL displayed the highest Vit.D3-responsiveness. In this context we demonstrated that the transcriptional Vit.D3-response concerning SPP1 and ALPL in human osteoblasts depended on the cell origin. The results indicate a higher bone remodeling activity of iliac crest than alveolar osteoblasts and support the growing evidence that a high osteoclast activity at the host-/donor bone interface may support graft integration

Murine model for Fusarium oxysporum invasive fusariosis reveals organ-specific structures for dissemination and long-term persistence

Peer reviewedPublisher PD

Common and specific amygdala-function perturbations in 2 depressed versus anxious adolescents

Context: Few studies directly compare amygdala function in depressive and anxiety disorders. 43 Data from longitudinal research emphasize the need for such studies in adolescents. 44 Objective: To compare amygdala response to varying attention and emotion conditions among 45 adolescents with Major Depressive Disorder (MDD) or anxiety disorders, relative to adolescents 46 with no psychopathology. 47 Design: Case-Control-Study. 48 Setting: Government Clinical Research Institute. 49 Participants: Eighty-seven adolescents matched on age, gender, intelligence, and social class: 26 50 with Major Depressive Disorder (MDD; 14 with and 12 without anxiety disorders), 16 with 51 anxiety disorders but no depression, and 45 with no psychopathology. 52 Main Outcome Measures: Blood oxygenated level dependent signal in the amygdala, measured 53 using event-related functional magnetic resonance imaging. During imaging, participants viewed 54 facial expressions (neutral, fearful, angry, happy) while attention was constrained (afraid, 55 hostility, nose width ratings) or unconstrained (passive-viewing). 56 Results: Left and right amygdala activation differed as a function of diagnosis, facial expression, 57 and attention-condition both when comorbid MDD/anxiety patients were included and excluded 58 (group-by-emotion-by-attention interactions: p-values≤.03). Focusing on fearful-face-viewing 59 events, anxiety and MDD patients both differed in amygdala responses from healthy participants 60 and from each other during passive-viewing. However, both MDD and anxiety patients, relative 61 to healthy participants, exhibited similar signs of amygdala hyper-activation to fearful faces when 62 rating subjectively experienced fear. 63 Conclusions: Adolescent MDD and anxiety disorders exhibit common and distinct functional 64 neural correlates during face processing. Attention modulates the degree to which common or 65 distinct amygdala perturbations manifest in these patient groups, relative to healthy peers